[Measurement of myocardial blood flow using N-13 ammonia dynamic PET-theory and methodology].
Positron emission tomography (PET) offers the potential capability of noninvasive measurement of regional myocardial blood flow (RMBF) in man. Because N-13 ammonia exhibits properties which to some extent resemble those of the radioactive microsphere, we developed a first-pass flow method for noninvasive measurement of RMBF. In the present method, RMBF was determined by dividing myocardial activity at time T by arterial input integrated from the injection start to that time, where time T is the endpoint of first circulation of N-13 ammonia. Also in the present method a time-activity curve of left atrium was used as the arterial input function to make the procedure totally noninvasive. To validate the present method, we compared it with the compartment analysis. 5 patients with hypertrophic cardiomyopathy (HCM) and with a considerably thickened ventricular wall, were selected for the comparison between the first-pass flow method and the compartment analysis. The relationship of RMBFs by the two methods was y = 1.8 + 1.097x-0.002037x2 (n = 30, SEE = 5.5), where x (ml/min/100 g) was obtained by the compartment analysis, while y (ml/min/100 g) by the first-pass flow method. The result indicated that both were almost identical in physiological flow range (less than 100 ml/min/100 g), but that the first-pass flow method underestimated RMBF in the higher flow range due to venous leakage of N-13 ammonia. As the conclusion, we could at least measure RMBF of HCM patient in the physiological flow range by the present method. The future extension of the method was discussed.
Endo
M
M
Division of Accelerator Research, National Institute of Radiological Sciences, Chiba.
Yoshida
K
K
Himi
T
T
Kagaya
A
A
Fukuda
H
H
Iinuma
T
T
Yamasaki
T
T
Tateno
Y
Y
Masuda
Y
Y
Inagaki
Y
Y
D000641:Ammonia; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology; D003326:Coronary Circulation; D006801:Humans; D008954:Models, Biological; D008955:Models, Cardiovascular; D009590:Nitrogen Radioisotopes; D014055:Tomography, Emission-Computed / Q000379:methods*
D009590:Nitrogen Radioisotopes; D000641:Ammonia